What gun should I buy next.

[Colorado Osprey]

... I don't want to have to buy some really odball cartridge.

Most any gun store will have ammo in .243WSSM....it's not that uncommon. In fact Winchester only produces rifles for it's last year in WSM and WSSM calibers. They also should not be too bad of a wallet burner because you can't load 30 rounds in a mag. 2 mags won't even hold 1 box of ammo. These boys are designed for umph and accuracy, not really high volume...it'll get to hot for that.

... Besides, I seriously doubt I'd get much under $1500 if I was gonna go for a dime-destroying tack driver. Not to mention the places I go shooting (North site, South site) wouldn't give me room to stretch it's legs, so to speak.

You can buy a guaraneed tack drived with a broach cut match barrel for less than you think. Uppers from $732 to put on your lower. Complete rifles are not much more than the cost of parts from him.
Here's the man that does it:
http://www.dtechsuperstore.com/WSSM%20page.htm

He's built 2 guns for me already and I have another on the way. If they don't shoot 1/4" MOA he'll fix it!

The ability to stretch it's legs...well I agree there...but he also makes them in 5.56 and 204 Ruger and shorter (under 300 yards) tack drivers in 6x45.

[roman gnome]

I didn't see the all-the-above answer!

But I bet you wouldn't hate a double bbl coach gun.

[Marlin]

It's been in the Blazer for the last couple of shoots. :P

I've just been shooting other things, Maybe Sat.

[The1andOnlyKC]

Well this was a tough one for me.

Since I got my 700 I have been facinated with making it shoot better (read making me shoot better) and also bolt guns in general. Actually thinking of getting another 700 in 30-06 or 300 win mag.

But I went for an AR because if you dont have one you better get one while you can.

[Hoser]

I say dont get any of the above.

Take the $$$ you might have set aside for a new toy and buy as many AR-15 lowers as you can. Might as well throw in at least one AR-10 lower too.

[The1andOnlyKC]

Yeah what Tom said too.

The prices on all of the lowers is going up.

I managed to get in before the price raise and get me 8 of 'em though

[Asha'man]

Another vote for AR, for all the reasons listed. Either that or several lowers and buy parts in the future. I built my rifle from a stripped lower without ever having had or seen an AR apart before, so it's not that hard.